Rear Brake caliper seized, vehicle vibrate, weak hand brake...

[samsamsam]

Hello,

My B7 A4 avant 6-speed got a seized caliper on the driver side rear. the rotor has rusted surface since caliper pad is not making contact. Once I press brake pedal the car vibrate like crazy. and steering also shaking as well. Not to mention the hand brake feels very weak, I have tried 30 mph and apply hand brake just feel a little bit brake...

I did some research, but I still not able to figure out some of my concerns:

1. If i replace caliper without bleeding, then go to dealer few days later ( so hard to make appointment at my place) to reflush brake system includes all brakes and clutch. Will that damage my new caliper? ( I know I will have few days got only 3 brakes, but it has been about two weeks.)

2. based on picture do I need a new rotor and pad? the pad still got decent amount left.

3. Could the soft hand brake caused by the seized caliper? or I still need to re-adjust the hand brake tension screw.

4. I found steering wheel shake while braking normally caused by front brakes. if I flush the whole system could that solve the problem?

I appreciate for any input. sorry for many questions all together.




Thanks!

 

[Charlie Farley]

first things , welcome aboard you'll find all the info you will ever need on here with plenty of guys to assist you.
I am not mechanic but what i can say is this, that disc is history chap, just not worth messing around with it, you could get it skimmed but not really worth it to be honest, the inner side of the disc maybe even worse , possibly corrosion on the piston is not helping and the carrier pins may be siezed also due to corrosion or contamination, you need to get things free and easy with the caliper.
You need to get the caliper off or away from the disc and get to the core of the problem chap , pads look to have a fair bit of meat left on them but your other rear may be worn down more, either way you may be needing a pair of rear disc's and possible new rear pads, i'd say discs were a minimum requirement.
sort out the siezed piston or what ever else is causing the problem then flush /bleed the whole system.
the brakes are biased towards the fronts but i would not drive with only one rear working, get the bits replaced and go from there, handbrake is self adjusting, might be prudent to remove all the wheels and check all four corners for wear/damage to rotor/pads.

 

[Charlie Farley]

Forgot to add, if the caliper piston is solid , which it may well be, then the handrake wont work on that side anyway, all the load is being applied to the other caliper, which you may find has a very worn pad now, you can see by the condition of the offending rotor how little contact is being made between pad and disc faces, all most nothing, that sort of condition has not happened overnight, thats a long standing caliper problem chap thats be going on for some time.

 

[Mike_B]

If you are going to do it yourself, you'll need the special tool to wind back the piston. They won't just push back into the caliper. I rather think you';ll find that once you've replaced the caliper, and have air in the brakes, you'll really not want to drive the car! If you are driving the car, could you let me know where and when so I can avoid being on the same road?

 

[A4DRB]

If the calliper is seized then handbrake wont work on that side and this could also cause vibrations when braking. You should also replace the discs and pads to save you time and money whilst the caliper is being done anyway, for dealer spec parts it is not expensive. If the piston in the calliper is seized totally and pushing the pad to the disc on one or both sides of the disc then the heat going through all these parts will be substantial and could quite easily have warped a disc, not to mention they dont look in the best of condition anyway. The brakes should be bled as soon as the caliper is fitted, there will be air in the system if not.

 

[Mike_B]

Forgive me saying this - but it has to be said. If you don't know what the result of not bleeding the brakes is, should you be working on those brakes?? Seriously. It's your life and other people's lives you're putting at risk.

 

[SootySport]

NO, NO, NO, don't drive it without bleeding the brakes. By the looks of it your whole braking system has been neglected for some years and needs a rebuild. No need to pay dealer prices for this job, any competent local garage will be able to do the work safely for you.

 

[Tim@G]

When removing a caliper you will 90% of the time need to bleed the other 3 anyway, unless your lucky enough to get away with just the one you changed. Personally I would strip the sliders and see if they are seized, clean up, grease up and rebuild, ease the rubber boot on the caliper piston back and give it a spray with
wd40 or rust inhibitor stuff leave it for a while then work it back and forth with your wind back tool. You might get lucky and be able to free it off. If you do need to remove and swap it for a new one then bleeding the air out the system before you drive it is a must. Your brakes will be rubbish.